First post here, so I'll intro myself then get to the car issue. Long read below...

Hi, my name is Steve, my wife and I have a 2008 HCH, it was bought brand new on the East coast but now we live in Texas.

About 3 weeks ago the car wouldn't start so I hooked it up to a home battery charger and it started up with no problems. We've driven it everywhere since then, even on a 300 mile road trip and back.

Yesterday I was sitting in the car, listening to the radio, waiting for my wife. After about 2mins on the "on" setting the gauge cluster started flickering and the radio shut off. There was thunder and lightning in the area, and the way the thing was behaving, it first led me to believe the car had been struck by lightning and was resetting... not likely, I know.

After a couple seconds, I thought the battery was dying although the IMA battery indicator showed three bars. I decided I should probably start the car so I did and it started up. The gauge cluster flickered some more and the engine was sputtering. I thought I should take it for a little drive to help recharge the batteries. When I pulled out of the parking spot, I had no power steering, and the engine was sputtering.

I drove around the parking lot without power steering, pulled back into a spot and turned off the car. When I went to turn it back on the windows wouldn't roll down, car wouldn't start, nothing. I got a jump from a friend and the car started right up and behaved properly.

I took the car to the local auto parts chain and had them test the battery... "bad battery" on his tester. He asked if I could start it, I said, "I hope..." I started it with no issues, and when tested again the tester showed, "bad diode in alternator". I'm a car guy, have two Chevy trucks and have had multiple small to large cars. I've replaced many alternators, so I look on the passenger side of the engine, see the pulleys and belts and locate what I thought was an alternator. So I said, "well, let me talk with the wife and see what we're going to do"

After leaving we called the local Honda dealer who immediately tried to get me to buy the battery "pack" for the car for $3,500... hahahaha! I told him twice it was the 12V under the hood that I needed and possibly a new alternator. He said he'd have to call me back but never did.

After doing some searching last night and today, I surprisingly couldn't find a replacement alternator, possibly because I've come to learn that these cars don't have them...?

So, after all of that:
1. Do these cars have alternators or not?
2. If not, what does the tester mean by "bad diode in alternator"
3. If there's not an alternator, will replacing the 12v battery fix the issue?

Thanks for reading and for any help you may be able to provide!

Steve in TX

 

You need a new 12V. There is no alternator. The electrical is all via the IMA system. It starts with the electrical mtr. but can also start with a normal starter in very low temps. when the Electric pack is low. H

 

I agree with what Harold said. A weak 12V battery will cause all sorts of issues with the electronic systems. The OEM battery in the hybrid is smaller than what the regular Civic uses however the regular battery is easy to find and will fit if you remove the plastic enclosure. It is known as a Group 51R (the R refers to 'reversed post' location).

Welcome and good luck!

Cheers,

Roger

 

The OEM battery in the hybrid is smaller than what the regular Civic uses

That's not true, its the same size battery but located on the opposite side.

 

Thank you all for your inputs!

I took the old battery out and replaced it with a new one in about 5mins, and the car is working great now. In fact, since I disconnected the battery in turn, reset the computer, I've actually increased my fuel mileage by at least 2mpg... is that normal?

If so, what would cause this to happen?

Thanks again to all who read and replied. Have a great day!

Stevein TX

 

Steve:

Some possibilities are that the IMA system has been converting more high voltage power in an attempt to recharge the failing 12V battery. This wasted energy had to be made up from forced regeneration which put an extra load on the engine meaning that more gas was consumed. Another possible factor is that the computerized systems may have been forced into a "fail-safe mode" in an attempt to cope with the inadequate 12V supply.

Glad to hear things are sorted out. From what I've read hot temperatures like in your area often lead to shorter lives for lead-acid batteries. Even where I live, 5 years is about all we can expect. I find it easier to replace the battery before problems develop.

Cheers,

Roger

 

Thanks Dream'R, I appreciate the response and explanation!

Great people on this board for sure!

Steve in TX